Start Shotcut and bring any video file to the timeline. Create at least five transitions to that clip. Then go to the History panel and in that list select any of the first two actions (e.g. Append playlist item or Insert into track). Shotcut will crash. You can also get Shotcut to crash after creating the transitions by hitting the Undo button many times rapidly. Sometimes when done with clicking Undo rapidly it will not crash right away until you try to select the clip in the timeline again then it will.